Antilock-picking device

ABSTRACT

An antilock-picking device for lever tumbler locks comprising a plurality of tumblers arranged to engage with a sliding bolt, comprising at least two shaped plates arranged along the same plane as two respective tumblers and mounted for rotation along an axis, each of the plates being provided an extension which is kept in engagement with an edge of the related tumbler coplanar with the other plate by resilient means and with a hook portion which when one of the tumblers is disengaged from the related extension is hooked with the coplanar tumbler due to the action of the said spring means thus preventing the lifting or raising movement thereof.

United States Patent [1 1 Errani Oct. 2, 1973 ANTILOCK-PICKING DEVICESerrature Affini, Via Oberdan, Faenza (Prov. of Ravenna), Italy Filed:Oct. 27, 1971 Appl. No.: 192,983

[56] References Cited U NlTED STATES PATENTS 6/]908 Ozorozy 70/352l0/l93l Lelity Brugemcrn 70/352 Primary Examiner-Robert L. WolfeAttorney-Henry T. Burke [57] ABSTRACT An antilock-picking device forlever tumbler locks comprising a plurality of tumblers arranged toengage with a sliding bolt, comprising at least two shaped platesarranged along the same plane as two respective tumblers and mounted forrotation along an axis, each of the plates being provided an extensionwhich is kept in engagement with an edge of the related tumbler coplanarwith the other plate by resilient means and with a hook portion whichwhen one of the tumblers is disengaged from the related extension ishooked with the coplanar tumbler due to the action of the said springmeans thus preventing the lifting or raising movement thereof.

2 Claims, 3 Drawing Figures PATENTEDBU 2W SHEET 1 0f 2 SYLMEMPATENTEDUBT "2191s saw 20F 2 k ANTllLOCK-PICKING DEVICE BACKGROUND OFTHE INVENTION The present invention relates to an antilock-pickingdevice for lever tumbler locks.

The device according to this invention is intended to prevent levertumbler locks from being picked by means of picklocks.

As known lever tumbler locks which can be controlled by double-profilekeys comprise a plurality of tumblers in the form of superimposedplates, in each of which a rectangular shaped opening is formed having aset of teeth along the two longer sides of the opening and arrangedopposite to one another. A pin member laterally projecting from thelocking bolt is caused to engage between the teeth of the plates. Theopposite teeth of each plate may be equal or different in height, whilethe distance between the outer ends of each pair of teeth opposite toone another is at least equal to the thickness of the pin member. Thus,by moving the plates relative to one another and in a direction normalto the locking direction of the sliding bolt, it is always possible toalign a set of superimposed teeth in such a manner so as a passage isdefined for the pin member of the locking bolt. This is done by aprofile of the key which is also shaped so as to cause, when the same isfurther rotated, the locking bolt to move for a first stretch, where thesaid alignment has been established. At the end of each half rotation ofthe key the pin member is again in an engagement position between theteeth. By further rotating the key the tumblers are caused to moveaccording to the other profile of the key and the alignment of theadjacent different set of superimposed teeth, thus obtaining a furthermovement of the locking bolt for a second stretch.

As is apparent from the above the locking bolt is moved when the sets ofopposite teeth are alternatively aligned in such a manner so as to leavethe passage free for the pin member of the locking bolt along thesliding line of the latter.

The locks of the above specified type, however, do not offer aparticular resistance to lock-picking in that the key hole, owing to thetwo opposite profiles formed in the key is rather large, thus allowing arelative easy access inside the lock and an easy use of picklocks.

As known the action of lock-picking consists in forcing back the lockingbolt thus making it possible to raise in succession the tumblers withwhich the pin member of the locking bolt is engaged.

SUMMARY OF THE INVENTION One object of the present invention is toprovide a device in which such lock-picking possibility is substantiallyeliminated.

The antilock picking device according to the invention is characterizedin that it comprises at least two shaped plates arranged in the sameplane as any pair of tumblers and mounted for rotation around an axis,each of the said plates being provided with an extension which is keptin engagement relationship with the edge of related tumbler coplanarwith the other plate by resilient means, and with a hook portion whichwhen one of the tumblers is disengaged from the related extension ishooked with the coplanar tumbler due to the action of the spring saidmeans, thus preventing the lifting movement thereof.

BRIEF DESCRIPTION OF THE DRAWING The invention will better appear fromthe following description with reference to the accompanying drawing, inwhich:

FIG. 1 is a general view of the inside of a lever tumbler lock providedwith the device according to this invention; and

FIG. 2 shows a device according to the invention in an operativecondition;

FIG. 3 is a perspective view of the device shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the abovefigures, a lever tumbler lock according to the invention comprises ahousing or casing generally indicated at 1 which is mounted on a faceplate element 2 by fixing means 3. From the side or back 44 of thehousing four threaded bushings 5 project upwards in which screws holdinga cover (not shown) tightening the same on the edge 6, are threaded.

The plate 2 has a frontal opening through which a locking or slidingbolt 7 can slide. The bolt 7 has a rear extension 8 formed with teeth 9in the lower portion thereof and with a straight eyelet opening 10 inwhich a guide pin 11 rigid with the bottom 4 of the housing I can slide.In this manner the sliding bolt 7 is guided in a horizontal direction,viewing FIG. 1'.

A pin member 12 is laterally rigid with the extension 8. The pin member12 extends normally to the sliding bolt 7 and is of a squarecross-section and allows engagement between the sliding bolt 7 and thetumblers 13. The latter can be any in number. In a preferred embodimentthe pin member 12 projects from both sides of the extension 8 and thetumblers 13 are arranged partly on the face in view of the extension 8and partly on the opposite face. For clarity sake, however, only one ofthem is illustrated in FIG. 1, the others being wholly similar to it.Each tumbler 13 is formed from a shaped plate provided with two eyeletsor windows 14 and 15 in engagement relationship with the threadedbushings 5, the latter guiding the said plates in a direction at rightangles relative to the moving direction of the sliding bolt 7.

Each plate has also a cut out portion 16 into which a double-profile keycan be inserted through the key hole 17in the housing 1.

A rectangular opening 18 is formed in each tumbler, along the longersides of which two sets 19 and 2t) of teeth spaced from one another areprovided which are arranged to receive the pin 12.

It should be noted that the distance between the opposite free ends ofthe teeth of the relative tooth sets 19 and 20 is just enough to allowthe passage of the pin member 12, and the teeth alternatively have thesame height. Of course the heights of the teeth in the various tumblerscan be different from one another so as to define two alternate sets ofsuperimposed teeth arranged to define a passage for the pin member 12only when the teeth of each set are moved relative to one another and tothe pin member 12 according to a relation corresponding to the code ofthe tumbler lock.

The movement of each tumbler occurs against the action of a rat-tail ortang spring 21 which has one end thereof rigid with the tumbler and theother end thereof abutting on the edge 6. The antilock-picking deviceaccording to the present invention consists of a pair of shaped plates22a and 22b pivoted on the pivot pin 23 rigid with the bottom 4 of thehousing 1. The plates 22a, 22b are housed in a recess of the housing 1and lie on the planes of two corresponding tumblers 13. The tumblerscoplanar with the plates 22a and 22b are indicated at 13a and 13b,respectively, in FIG. 2..

The plates 22a and 22b are substantially equal in shape. They haveextensions 24 and 25 shaped in such a manner so as due to the urgingaction of the rat-tail or tang springs 25 the free ends thereof engagesuitably inclined portions of the rear edges of the tumblers 13b and1311, respectively. The plates 22a and 2212 are also formed with twohooked portions 27 and 28 arranged to engage, as will better appearhereinafter, with relative stepped portions 29 and 30 formed in thecoplanar tumblers 13a and 13b.

The operation of the antilock-picking device according to the inventionis as follows. As described above the lock-picking action consists inraising the tumblers so as to cause the sets of teeth 19 and to definepassages at the level of the pin member 12 thus allowing the slidingmovement thereof. Y

With the device according to the present invention this sliding movementis prevented in that when one of the tumblers 13a and 13b is caused toraise, the other pin is hooked and thus cannot be raised. In fact, bycausing the tumbler 13b to raise, the extension 24 of the plate 22a isno more engaged and due to the action of the spring 26 the plate 22a iscaused to rotate and the hook portion 27 engages with the step portion29 of the tumbler 13a thus preventing the raising movement thereof.

It should be noted that the lifting movement of the two tumblers 13a and13b at the same time is uneffective in that in order to free the passagefor the pin member 12 it is necessary to lift one of them to a greateror lesser extent relative to the other according to the code of thelock, this being instead possible by making use of a proper key.

l claim:

1. An antilock-picking device for lever tumbler locks comprising aplurality of tumblers arranged to engage with a sliding bolt,characterized in that it comprises at least two shaped plates arrangedin the same plane as any pair of said tumblers and mounted for rotationaround an axis, each of said plates being provided with an extensionwhich is kept in engagement relationship with an edge of the relatedtumbler coplanar with the other plate by resilient means and with a hookportion which when one of the tumblers is disengaged from the relatedextension is hooked with the coplanar tumbler due to the action of thesaid spring means thus preventing the lifting movement thereof.

2. A device as claimed in claim 1, wherein the said spring meansconsists of rat-tail or tang springs secured at one end thereof to therelated plate and abutting on the inner surface of the housing of thelock with the other end thereof.

UNITED STATES PATENT OFFICE I CERTIFICATE CORRECTIQN Patent No. 3,762,192 V Dated October 2, 1973 Inventor(s) I Deo Errani It is certifiedthat error appears in theabove-idntified patent and that said LettersPatent are hereby corrected as shown below:

First page, left-hand colunfin, after [21] Appl. No.: 192,983",

the following has been omitted:

-- Foreign Application Priority Data October 30, 1970 Italy. 3600 A/TOSigned and sealed this 9th day of April 197L (SEAL) Attest:

EDWARD M.FLETCHER,JR. Attesting Officer C. MARSHALL DANN Commissioner ofPatents USCOMM-DC 60376-P69 [1.51 GOVERNMENT PRINTING OFFICE: l9,0-365-3!

1. An antilock-picking device for lever tumbler locks comprising aplurality of tumblers arranged to engage with a sliding bolt,characterized in that it comprises at least two shaped plates arrangedin the same plane as any pair of said tumblers and mounted for rotationaround an axis, each of said plates being provided with an extensionwhich is kept in engagement relationship with an edge of the relatedtumbler coplanar with the other plate by resilient means and with a hookportion which when one of the tumblers is disengaged from the relatedextension is hooked with the coplanar tumbler due to the action of thesaid spring means thus preventing the lifting movement thereof.
 2. Adevice as claimed in claim 1, wherein the said spring means consists ofrat-tail or tang springs secured at one end thereof to the related plateand abutting on the inner surface of the housing of the lock with theother end thereof.